/** * ----------------------------- JSTORAGE ------------------------------------- * Simple local storage wrapper to save data on the browser side, supporting * all major browsers - IE6+, Firefox2+, Safari4+, Chrome4+ and Opera 10.5+ * * Copyright (c) 2010 Andris Reinman, andris.reinman@gmail.com * Project homepage: www.jstorage.info * * Licensed under MIT-style license: * * Permission is hereby granted, free of charge, to any person obtaining a copy * of this software and associated documentation files (the "Software"), to deal * in the Software without restriction, including without limitation the rights * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell * copies of the Software, and to permit persons to whom the Software is * furnished to do so, subject to the following conditions: * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE * SOFTWARE. */ /** * USAGE: * * jStorage requires Prototype or jQuery! If jQuery is used, then * jQuery-JSON (http://code.google.com/p/jquery-json/) is also needed. * (jQuery-JSON needs to be loaded BEFORE jStorage!) * * Methods: * * -set(key, value) * $.jStorage.set(key, value) -> saves a value * * -get(key[, default]) * value = $.jStorage.get(key [, default]) -> * retrieves value if key exists, or default if it doesn't * * -deleteKey(key) * $.jStorage.deleteKey(key) -> removes a key from the storage * * -flush() * $.jStorage.flush() -> clears the cache * * can be any JSON-able value, including objects and arrays. * */ (function($){ if(!$ || !($.toJSON || Object.toJSON)) throw new Error("jQuery or Prototype needs to be loaded before jStorage!"); $.jStorage = { /* Version number */ version: "0.1", /* This is the object, that holds the cached values */ _storage: {}, /* Actual browser storage (localStorage or globalStorage['domain']) */ _storage_service: {jStorage:"{}"}, /* DOM element for older IE versions, holds userData behavior */ _storage_elm: null, /* function to encode objects to JSON strings */ json_encode: $.toJSON || Object.toJSON, /* function to decode objects from JSON strings */ json_decode: $.evalJSON || function(str){ return String(str).evalJSON(); }, ////////////////////////// PRIVATE METHODS //////////////////////// /** * Initialization function. Detects if the browser supports DOM Storage * or userData behavior and behaves accordingly. * @returns undefined */ _init: function(){ /* Check if browser supports localStorage */ if("localStorage" in window){ this._storage_service = localStorage; } /* Check if browser supports globalStorage */ else if("globalStorage" in window){ this._storage_service = globalStorage[document.domain] } /* Check if browser supports userData behavior */ else{ this._storage_elm = document.createElement('link') if("addBehavior" in this._storage_elm){ /* Use a DOM element to act as userData storage */ this._storage_elm.style.behavior = 'url(#default#userData)'; /* userData element needs to be inserted into the DOM! */ document.getElementsByTagName('head')[0].appendChild(this._storage_elm); this._storage_elm.load("jStorage"); try{ var data = this._storage_elm.getAttribute("jStorage") }catch(E){var data = "{}"} if(data && data.length){ this._storage_service.jStorage = data; } }else{ this._storage_elm = null; return; } } /* if jStorage string is retrieved, then decode it */ if("jStorage" in this._storage_service && this._storage_service.jStorage){ try{ this._storage = this.json_decode(this._storage_service.jStorage); }catch(E){this._storage_service.jStorage = "{}";} }else{ this._storage_service.jStorage = "{}"; } }, /** * This functions provides the "save" mechanism to store the jStorage object * @returns undefined */ _save:function(){ if(this._storage_service){ try{ this._storage_service.jStorage = this.json_encode(this._storage); }catch(E){/* probably cache is full, nothing is saved this way*/} // If userData is used as the storage engine, additional if(this._storage_elm){ try{ this._storage_elm.setAttribute("jStorage",this._storage_service.jStorage) this._storage_elm.save("jStorage"); }catch(E){/* probably cache is full, nothing is saved this way*/} } } }, /** * Function checks if a key is set and is string or numberic */ _checkKey: function(key){ if(!key || (typeof key != "string" && typeof key != "number")){ throw new TypeError('Key name must be string or numeric'); } return true; }, ////////////////////////// PUBLIC METHODS ///////////////////////// /** * Sets a key's value. * @param {String} key - Key to set. If this value is not set or not * a string an exception is raised. * @param value - Value to set. This can be any value that is JSON * compatible (Numbers, Strings, Objects etc.). * @returns the used value */ set: function(key, value){ this._checkKey(key); this._storage[key] = value; this._save(); return value; }, /** * Looks up a key in cache * @param {String} key - Key to look up. * @param {mixed} def - Default value to return, if key didn't exist. * @returns the key value, default value or */ get: function(key, def){ this._checkKey(key); if(key in this._storage) return this._storage[key]; return def?def:null; }, /** * Deletes a key from cache. * @param {String} key - Key to delete. * @returns true if key existed or false if it didn't */ deleteKey: function(key){ this._checkKey(key); if(key in this._storage){ delete this._storage[key]; this._save(); return true; } return false; }, /** * Deletes everything in cache. * @returns true */ flush: function(){ this._storage = {}; this._save(); return true; } } // load saved data from browser $.jStorage._init(); })(typeof jQuery != "undefined" && jQuery || $);